JPH0454089Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention is a heat-shrinkable film (hereinafter referred to as ``film'') that is used to package contents (hereinafter referred to as ``film packaging''). It is used in the technical field of airtightly sealing contents by shrinking them by spraying water vapor, and particularly relates to a device for this purpose.

[Conventional technology]

An example of this type of device is one proposed by the applicant and disclosed in Japanese Utility Model Application No. 110510/1983. This device has a box that opens downward above a belt conveyor that transports film packages, and makes water vapor eject downward from the top of the inside of the box. The film packaging body can be moved up and down between the inside of the box and the film is thermally shrunk by the heat of the steam filling the inside of the box. In this apparatus, when the film is shrunk, the film wrapper completely enters the inside of the box, so that the film is shrunk very effectively.

[The problem that the idea aims to solve]

However, in the above-mentioned known apparatus, since the portion of the film in contact with the belt conveyor does not come into direct contact with water vapor, there is a problem in that the film does not shrink sufficiently in this portion.

The present invention solves this problem and allows the film to shrink uniformly and effectively by bringing water vapor into direct contact with the entire periphery of the film package, and also maintains a stable temperature without using a large-capacity steam supply device. It is an object of the present invention to provide a shrinking device for packaging plastic film that enables uniform shrinkage at all times.

[Means to solve the problem]

According to the present invention, the above-mentioned purpose is to have a conveyor that runs through an inlet and an outlet provided on the side of the box, and to spray water vapor onto the film packaging on the conveyor inside the box. In the apparatus for heat-shrinking a film, the conveyor has a large number of ventilation holes, and steam spraying units are disposed above and below the film package on the conveyor, and spray water vapor onto the film package from both directions above and below, A steam reservoir is formed at an upper position inside the box, and the steam reservoir includes a steam supply pipe that supplies steam from outside the box to the steam reservoir, and a suction pipe that sucks out the steam in the steam reservoir. This is achieved by providing a pipe, and a blower is attached to the suction pipe to suck out the steam in the steam reservoir and supply it to the steam blowing body.

In this case, the steam reservoir chamber may be provided with a temperature sensor and a control means for controlling the steam supply of the steam supply pipe so that the temperature inside the steam reservoir chamber is maintained at a set temperature. preferable.

[Effect]

According to the present invention, the film package is blown with water vapor sucked out from the steam reservoir chamber by the blower and supplied to the steam spraying body from above and through the vent of the conveyor from the steam spraying body below. Therefore, the film shrinks uniformly and effectively over the entire surface of the film package. that time,
In the present invention, since the steam reservoir chamber is provided inside the box body, the steam reservoir chamber has the function of keeping the steam warm and as a buffer, and even if the steam is blown out from the steam spraying body, the steam reservoir chamber as the supply side has the function of keeping the steam warm and as a buffer. Temperature and pressure hardly fluctuate, resulting in stable contraction. When a temperature sensor is disposed in the steam reservoir, the control means controls the supply of steam through the steam supply pipe to further stabilize conditions such as the temperature inside the steam reservoir.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of the device of this embodiment.

In Fig. 1, numeral 1 is a box whose interior forms a steam chamber. An inlet 1A and an outlet 1B are provided on both sides of the box 1, and a conveyor 2 for conveying the film package P runs through the inlet 1A and the outlet 1B. . The carry-in port 1A and the carry-out port 1B are set to be large enough to carry the film package P into and out of the box 1, and the film package P can be freely carried in and out. At the same time, curtains 3A and 3B are hung in order to control leakage of water vapor from the inside as much as possible.

The conveyor 2 is stretched over sprockets 2A and 2B disposed outside the box 1, and is driven by the sprockets 2A and 2B to travel in the S direction shown in the figure. The conveyor 2 itself had a large number of ventilation holes.
For example, it is formed of a wire mesh belt.

At the upper and lower positions of the conveyance surface of the conveyor 2, nozzle tubular steam spraying bodies 4A and 4B that spray steam onto the film package P from above and below extend in a direction perpendicular to the plane of the paper. The steam spraying bodies 4A, 4B
does not receive water vapor directly from a water vapor supply source provided outside the device, but receives water vapor from a water vapor storage chamber 5 corresponding to a buffer in this embodiment.

The steam storage chamber 5 is arranged in the upper part of the internal space of the box body 1, and the bottom thereof has an opening 5A at a position corresponding to the upper part of the steam spraying body 4A. Conduit pipes 6A, 6B, 6C, and 6D, which are water vapor supply pipes branched from a supply pipe 6 from a water vapor supply source (not shown) via a control valve 7, enter the steam storage chamber 5 at right angles to the plane of the paper. Each conduit has a nozzle-shaped pore formed therein so that the water vapor storage chamber 5 is uniformly filled with a large amount of water vapor under low pressure. Further, a suction pipe 8A is disposed approximately in the center of the steam reservoir chamber 5 so as to open inside the steam reservoir chamber 5, and a suction pipe 8A is disposed on the outer surface of the apparatus (in the figure, the position on the back side of the page). Suction fan 8
(Blower). The pipe 9 on the discharge side of the side suction fan 8 is connected to the steam blowing bodies 4A, 4B, so as to supply the steam sucked out from the steam storage chamber to the steam blowing bodies 4A, 4B. It's summery. Further, from the bottom wall 5B of the steam reservoir chamber 5, a plurality of curtains 5C similar to the curtains 3A and 3B described above are suspended before and after the steam spraying body 4A. Moreover, as a preferable form, in this embodiment, the water vapor reservoir chamber 5
A temperature sensor 10 is disposed inside, and the control valve 7 is opened and closed via a control means (not shown) so that the temperature inside the steam storage chamber 5 is maintained at a set temperature.

Note that a space 11 is maintained between the upper part of the box 1 and the steam storage chamber 5, and an upper suction fan 12 is provided in the upper part of the space 11, and a condenser 13 is provided through a conduit 12A.
It is connected to the. A cold water nozzle 13A for condensing water is arranged in the condenser 13, and the condensed water is drained from a drain port 13B.

On the other hand, a slightly inclined receiving plate 14 is provided at the lower part of the box body, that is, the lower side of the conveyor 2, and a drain port 14A through which water droplets drip is provided at the inclined lower part (near the right end in the figure). . Furthermore, an opening is provided approximately in the center of the receiving plate 14, and the above-mentioned condenser 13 is connected to the condenser 13 through a conduit 15.

Next, the operation of the apparatus of this embodiment as described above will be explained.

First, the temperature inside the steam reservoir chamber 5 is detected by the temperature sensor 10, and the control valve 7 is opened and closed by the control means, so that the steam reservoir chamber 5 is always kept at the set temperature by the steam. Note that since the steam reservoir chamber 5 is provided within the box body 1, no heat escapes to the outside, and the steam within the steam reservoir chamber 5 is effectively kept warm.

The steam in the steam storage chamber 5 is sucked out from the suction pipe 8A by the side suction fan 8, and then is sucked out from the steam blowing bodies 4A, 4B via the pipe 9. on the other hand,
From the entrance 1A, the film package P is brought into the box 1 by the conveyor 2, and the curtains 3A, 5 are brought into the box 1.
C and passes between the steam spraying bodies 4A and 4B. At this time, the upper and lower surfaces of the film package P are simultaneously heated by both the steam from the upper steam spraying body 4A and the steam passing through the mesh of the conveyor 2 from the lower steam spraying body 4B, so that the film is uniformly heated. Shrink. After that, the film package P is transferred to the curtains 5C and 3B by the conveyor 2.
The product passes through the exit port 1B and is taken out as a product.

Since the steam storage chamber 5 has a large volume compared to the amount of steam blown out from the steam blowing bodies 4A and 4B, even if the capacity of the steam supply source is not high,
Pressure remains stable.

In the process of spraying water vapor onto the film package, a plurality of curtains 5C are suspended in front and behind the water vapor spraying area where the water vapor spraying bodies 4A, 4B are located, so the area is fairly sealed.
Moreover, although the water vapor is designed to return to the water vapor storage chamber 5 through the opening 5A, leakage of water vapor to the outside of the above-mentioned area cannot be avoided due to gaps in the curtain and movement thereof. Furthermore, although the blown water vapor is designed to rise and be collected in the water vapor storage chamber 5 as described above, a portion of it flows downward. Therefore, in the upper part of the box, it passes through the upper suction fan 12, and in the lower part of the box, it passes through the conduit 15.
The steam leaking from the steam spraying areas is introduced into the condenser 13, where it is condensed and discharged from the drain port 13B. Further, water that has turned into water droplets is received by the inclined receiving plate 14 and discharged from the drain port 14A.

Although the present invention is as described above, the supplied water vapor does not need to be at a significantly higher pressure, and a level of 3 to 1.02 atmospheres relative to atmospheric pressure is sufficient.

[Effect of idea]

Since the present invention is as described above, the film packaging body can be shrunk under almost the same conditions on the upper and lower surfaces, and it is possible to obtain the effects of improving the shrinkability of the film and improving the quality and aesthetic appearance of the product. Furthermore, since it is equipped with a steam storage chamber, even if the capacity of the steam supply source is not very large, steam can always be sprayed under certain conditions, making the above effects even more reliable. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an apparatus according to an embodiment of the present invention. 1...Box body, 1A...Carry-in port, 1B...Carry-out port, 2...Conveyor, 4A, 4B...Steam blowing body, 5...Steam storage chamber, 6A, 6B, 6C, 6D
...Steam supply pipe (conduit), 8A ...Suction pipe, 1
0...Temperature sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A conveyor that runs through an inlet and an outlet provided on the side of the box body, and sprays water vapor onto the film packaging on the conveyor inside the box body. In the apparatus for heat-shrinking a film, the conveyor has a large number of ventilation holes, and steam spraying units are disposed above and below the film package on the conveyor, and spray water vapor onto the film package from both directions above and below, A steam reservoir is formed at an upper position inside the box, and the steam reservoir includes:
A steam supply pipe that supplies steam into the steam reservoir from outside the box and a suction pipe that sucks out the steam inside the steam reservoir are provided, and the suction pipe sucks out the steam inside the steam reservoir and blows out the steam. A packaging plastic film shrinking device, characterized in that a blower for supplying air to the body is attached. (2) A temperature sensor is installed in the steam reservoir to maintain the temperature within the steam reservoir at the set temperature.
2. The packaging plastic film shrinking apparatus according to claim 1, further comprising a control means for controlling the water vapor supply from the water vapor supply pipe.